Hitherto, a heater, wafer prober and the like wherein a base material made of metal such as stainless steel or aluminum alloy is used has been used in semiconductor producing/examining devices and so on, examples of which include an etching device, a chemical vapor deposition device and the like.
However, such a heater made of metal has the following problems.
First, the thickness of the heater plate must be made as thick as about 15 mm since the heater is made of metal. Because in a thin metal plate, a bend, a strain and so on are generated on the basis of thermal expansion resulting from heating so that a silicon wafer put on the metal plate is damaged or inclined. However, if the thickness of the heater plate is made thick, a problem that the heater becomes heavy and bulky arises.
The temperature for heating is controlled by changing the voltage or current amount applied to resistance heating elements. However, since the metal plate is thick, the temperature of the heater plate does not follow the change in the voltage or current amount promptly. Thus, a problem that the temperature is not easily controlled is caused as well.
Thus, JP Kokai Hei 4-324276 proposes a ceramic heater wherein: aluminum nitride, which is a non-oxide ceramic having a high thermal conductivity and a high strength, is used as a substrate; a resistance heating element and a conductor-filled through hole comprising tungsten are made in this aluminum nitride substrate ; and nichrome wires as external terminals are brazed thereto.